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251.
This study tested competing predictions about the implications of Internet use for traditional inequities in social support availability. Using survey data collected as part of the Pew Internet and American Life Project, inequities in social support availability stemming from demographic and network-related factors were examined among non-users, Internet users, and Internet users who also participated in a social network site (SNS). The results offered evidence consistent with the social compensation perspective. Traditional inequities in support availability related to age, race, and total network size persisted among respondents who did not use the Internet, but were less evident or absent among Internet users and/or Internet users who participated in an SNS. Using the Internet to connect with others appeared to be an important mechanism through which inequality in support availability was mitigated. 相似文献
252.
The views of specialists (academics, librarians, publishers and information scientists) on trends in scholarly communications were canvassed by means of structured questions. A greater commonality of views was found than might have been expected. 相似文献
253.
Susan J. Brown Alan M. Nevill Stuart A. Monk Steve R. Otto W. Scott Selbie Eric S. Wallace 《Journal of sports sciences》2013,31(14):1483-1491
Abstract Previous studies on the kinematics of the golf swing have mainly focused on group analysis of male golfers of a wide ability range. In the present study, we investigated gross body kinematics using a novel method of analysis for golf research for a group of low handicap female golfers to provide an understanding of their swing mechanics in relation to performance. Data were collected for the drive swings of 16 golfers using a 12-camera three-dimensional motion capture system and a stereoscopic launch monitor. Analysis of covariance identified three covariates (increased pelvis–thorax differential at the top of the backswing, increased pelvis translation during the backswing, and a decrease in absolute backswing time) as determinants of the variance in clubhead speed (adjusted r 2 = 0.965, P < 0.05). A significant correlation was found between left-hand grip strength and clubhead speed (r = 0.54, P < 0.05) and between handicap and clubhead speed (r = ?0.612, P < 0.05). Flexibility measures showed some correlation with clubhead speed; both sitting flexibility tests gave positive correlations (clockwise: r = 0.522, P < 0.05; counterclockwise: r = 0.711, P < 0.01). The results suggest that there is no common driver swing technique for optimal performance in low handicap female golfers, and therefore consideration should be given to individual swing characteristics in future studies. 相似文献
254.
Markus J. Klusemann David B. Pyne Carl Foster Eric J. Drinkwater 《Journal of sports sciences》2013,31(14):1463-1471
Abstract Differences in physiological, physical, and technical demands of small-sided basketball games related to the number of players, court size, and work-to-rest ratios are not well characterised. A controlled trial was conducted to compare the influence of number of players (2v2/4v4), court size (half/full court) and work-to-rest ratios (4x2.5 min/2x5 min) on the demands of small-sided games. Sixteen elite male and female junior players (aged 15–19 years) completed eight variations of a small-sided game in randomised order over a six-week period. Heart rate responses and rating of perceived exertion (RPE) were measured to assess the physiological load. Movement patterns and technical elements were assessed by video analysis. There were ～60% more technical elements in 2v2 and ～20% more in half court games. Heart rate (86 ± 4% & 83 ± 5% of maximum; mean ± SD) and RPE (8 ± 2 & 6 ± 2; scale 1–10) were moderately higher in 2v2 than 4v4 small-sided games, respectively. The 2v2 format elicited substantially more sprints (36 ±12%; mean ±90% confidence limits) and high intensity shuffling (75 ±17%) than 4v4. Full court games required substantially more jogging (9 ±6%) compared to half court games. Fewer players in small-sided basketball games substantially increases the technical, physiological and physical demands. 相似文献
255.
Abstract The influence of the Cardan rotation sequence on the orientation angles for joints is well known but has not been explored for dynamic sports movements. The purpose of this study is to establish the influence of Cardan rotation sequence on the orientation angles of the ankle, knee, and hip of the support leg and pelvis during dynamic sports movements, typified by a maximal instep kick in soccer. We found that: (a) the X (flexion/extension) axis rotations provide data that are robust for any sequence used other than the YXZ sequence, although the Y (abduction/adduction) and Z (internal/external) axes rotations are variable in both shape and offset magnitude; (b) the preferred rotation sequence is either XYZ or XZY for dynamic sports movements, although for the soccer kick the XYZ rotation sequence has been widely used and so this is recommended as a standard; and (c) most uncertainties exist in the Y and Z axes and are most apparent at the beginning of the movement. Where uncertainty exists in identifying Y and Z axes orientations, the integrated angular velocity may be considered as an alternative to determine the relative changes in segment orientation. 相似文献
256.
This study was designed to assess the impact of taking a high quality picture book home from school daily on the at-home reading behaviors of young children and/or family members from middle and low SES backgrounds. Eighty children representing two study groups (treatment & no-treatment comparison) and two socioeconomic groups (Head Start & middle-class) composed the study sample. Treatment children selected picture books at school daily to take home over a 12-week period. Child and family picture book reading behaviors were assessed by weekly random telephone surveys. Findings indicate that taking a picture book home daily more than doubled the number of books read at home for both middle-class and Head Start treatment children over their no-treatment comparison counterparts and significantly increased the amount of time Head Start treatment children were involved in reading each day. The practicality of making high quality picture books available for preschool children to take home and the implications of increased at-home reading behaviors are discussed. 相似文献
257.
Tyler Goldberg David Horvath Eric Neagle 《Library Collections, Acquisitions, and Technical Services》2001,25(4):37
It is broadly acknowledged that effective serials management supports and requires a close link between the staff in technical and public services. More recently, new technological opportunities combined with changes in library organization and administration have greatly facilitated this linkage. The nature and structure of a library’s organization can aid in and benefit from this connectedness. Departments in the University of Louisville’s public and technical services areas began a cooperative effort to maintain serials records in the online catalog in the early 1990s. With reorganization in the late 1990s, a new team structure emerged which further facilitated this effort. In return, this cooperation and the tools that it has created support the teams in a new user-centered approach to serials management. 相似文献
258.
Eric C. Haakonssen Martin Barras Louise M. Burke David G. Jenkins David T. Martin 《European Journal of Sport Science》2016,16(6):645-653
The aims of this study were to describe normative values and seasonal variation of body composition in female cyclists comparing female road and track endurance cyclists, and to validate the use of anthropometry to monitor lean mass changes. Anthropometric profiles (seven site skinfolds) were measured over 16 years from 126 female cyclists. Lean mass index (LMI) was calculated as body weight?×?skinfolds?x. The exponent (x) was calculated as the slope of the natural logarithm of body weight and skinfolds. Percentage changes in LMI were compared to lean mass changes measured using dual-energy X-ray absorptiometry (DXA) in a subset of 25 road cyclists. Compared to sub-elite and elite cyclists, world class cyclists were (mean [95% CI]) 1.18?kg [0.46, 1.90] and 0.60?kg [0.05, 1.15] lighter and had skinfolds that were 7.4?mm [3.8, 11.0] and 4.6?mm [1.8, 7.4] lower, respectively. Body weight (0.41?kg [0.04, 0.77]) and skinfolds (4.0?mm [2.1, 6.0]) were higher in the off-season compared to the early-season. World class female road cyclists had lower body weight (6.04?kg [2.73, 9.35]) and skinfolds (11.5?mm [1.1, 21.9]) than track endurance cyclists. LMI (mean exponent 0.15 [0.13, 0.18]) explained 87% of the variance in DXA lean mass. In conclusion, higher performing female cyclists were lighter and leaner than their less successful peers, road cyclists were lighter and leaner than track endurance cyclists, and weight and skinfolds were lowest early in the season. LMI appears to be a reasonably valid tool for monitoring lean mass changes. 相似文献
259.
Katie Eklund Sarah L. DeMarchena Eric Rossen Jared T. Izumi Kelly Vaillancourt Shawna Rader Kelly 《Psychology in the schools》2020,57(4):489-501
The school setting represents the most common setting by which youth receive mental and behavioral health (MBH) services (Farmer et al., 2003, Psychiatr Serv, 54, 60–66). Nevertheless, many school psychologists are not providing MBH services despite the high prevalence of need. Additional research is needed to understand factors leading to these deficits, as well as potential solutions to ameliorate these concerns. The current study surveyed 341 school psychologists across seven states and found current ratios are one school psychologist for every 1,500–2,000 students. Study results suggest school psychologists are providing a half to full day of universal, prevention-oriented MBH services each week whereas more targeted, direct services (e.g., individual or small group counseling) are offered 1–4 hr each week. The school psychologist-to-student ratios also demonstrated a statistically significant and inverse association with the provision of targeted MBH services, with higher ratios resulting in fewer MBH services. Respondents provided potential solutions for how to expand the delivery of MBH services within schools, including increased awareness and support among school and district administrators, as well as access to training and professional development related to MBH services. 相似文献
260.